81199409760 has 576 divisors, whose sum is σ = 331564326912. Its totient is φ = 17692950528.

The previous prime is 81199409723. The next prime is 81199409833. The reversal of 81199409760 is 6790499118.

81199409760 is a `hidden beast` number, since 81 + 1 + 99 + 409 + 76 + 0 = 666.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 81199409697 and 81199409706.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 133771377 + ... + 133771983.

It is an arithmetic number, because the mean of its divisors is an integer number (575632512).

Almost surely, 2^81199409760 is an apocalyptic number.

81199409760 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81199409760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165782163456).

81199409760 is an abundant number, since it is smaller than the sum of its proper divisors (250364917152).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81199409760 is a wasteful number, since it uses less digits than its factorization.

81199409760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1235 (or 1224 counting only the distinct ones).

The product of its (nonzero) digits is 979776, while the sum is 54.

The spelling of 81199409760 in words is "eighty-one billion, one hundred ninety-nine million, four hundred nine thousand, seven hundred sixty".